Answer: Hello there!
We know that:
This means that two of two objects whit the same size ( volume) the heaviest one is the more dense object.
The 4 that we have here are:
Air, Pumpkin pie, Whipped cream, and Steel
It is easy to assume that the steel is the more dense object.
The pumpkin pie comes second
third is the whipped cream, which is cream with a lot of tiny air bubbles inside
the less dense object is the air.
then the order is:
Steel, pumpkin pie, whipped cream, air.